Retrieve_Current_Context_Token (CTXRCC, CTX4RCC)

CTXRCC is for AMODE(31) callers.
CTX4RCC is for AMODE(64) callers and allows parameters in 64 bit addressable storage.

A resource manager calls the Retrieve_Current_Context_Token service to obtain the context token for the currently active context. The token can be used in subsequent calls to other context services to identify that context.

Note: The Retrieve_Current_Context_Token service is intended to be used to obtain the context token of the active context of the current dispatchable unit of work.

Environment

The requirements for the resource manager are:

Minimum authorization:

None

Dispatchable unit mode:

Task mode

Cross memory mode:

Any PASN, any HASN, any SASN

AMODE:

31 bit (CTXRCC)
64 bit (CTX4RCC)

ASC mode:

Primary or AR

Interrupt status:

Enabled for I/O and external interrupts

Locks:

Unlocked

Control parameters:

Control parameters must be in the primary address space and addressable by the resource manager.

Programming requirements

Either link edit the resource manager's object code with the linkable stub routine CTXCSS (31 bit) or CTX4CSS (64 bit) from SYS1.CSSLIB, or LOAD and CALL the service. The high level language (HLL) definitions for the callable service are:

HLL Definition	Description
CTXASM	390 Assembler declarations
CTXC	C/390 declarations

Restrictions

None.

Input register information

Before issuing the call, the resource manager does not have to place any information into any register unless using it in register notation for the parameters, or using it as a base register.

Output register information

When control returns to the resource manager, the GPRs contain:

Register: Contents
0-1: Used as work registers by the system
2-13: Unchanged
14: Used as a work register by the system
15: Return code

When control returns to the resource manager, the ARs contain:

Register: Contents
0-1: Used as work registers by the system
2-13: Unchanged
14-15: Used as work registers by the system

Some resource managers depend on register contents remaining the same before and after issuing a call. If the system changes the contents of registers on which the resource manager depends, the resource manager must save them before calling the service, and restore them after the system returns control.

Performance implications

None.

Syntax

Write the call as shown in the syntax diagram. You must code the parameters in the CALL statement as shown.

CALL CTXRCC

(return_code
,context_token)

CALL CTX4RCC

(return_code
,context_token)

Parameters

The parameters are explained as follows:

return_code

Returned parameter

Type: Integer
Character Set: N/A
Length: 4 bytes

Provides the return code for the call.

,context_token

Returned parameter

Type: Character string
Character Set: No restriction
Length: 16 bytes

The context_token identifies the context that is currently active.

ABEND codes

The call might result in an abend X'AC7' with a reason code of either X'00220000' or X'00220001'. See z/OS MVS System Codes for the explanations and actions.

Return codes

When the service returns control to the resource manager, GPR 15 and return_code contain a hexadecimal return code.

Return Code in: Hexadecimal Equate Symbol	Meaning and action
0 CTX_OK	Meaning: Successful completion. Action: None.
103 CTX_INTERRUPT_INV	Meaning: Program error. The caller is disabled. The system rejects the service call. Action: Check program logic for probable coding error. Correct the problem and reissue service.
104 CTX_MODE_INV	Meaning: Program error. The caller is not in task mode. The system rejects the service call. Action: Check program logic for probable coding error. Correct the problem and reissue service.
105 CTX_LOCKS_HELD	Meaning: Program error. The resource manager is holding one or more locks; no locks must be held. The system rejects the service call. Action: Check the resource manager for a probable coding error. Correct the resource manager and rerun it.
107 CTX_UNSUPPORTED_RELEASE	Meaning: The release of MVS™ does not support this service. The service stub has been linked on a system that does not support the correct level of Context Services. Action: Remove the resource manager from the system, and install it on a system that supports the correct level of Context Services. Then rerun the resource manager.
36A CTX_DU_TERMINATING	Meaning: Program error. The dispatchable unit associated with the specified context is terminating. The system rejects the service call. Action: Check the resource manager for a probable coding error. Correct the resource manager and rerun it.
FFF CTX_UNEXPECTED_ERROR	Meaning: System error. The service that was called encountered an unexpected error. The system rejects the service call. Action: Search problem reporting databases for a fix for the problem. If no fix exists, contact the IBM® Support Center.

Example

In the pseudocode example, the resource manager issues a call to retrieve the context token of the current context. Storage for the call parameters has been allocated.

⋮
C_TOKEN = ''B;
CALL CTXRCC(RC,C_TOKEN);
IF RC ¬= CTX_OK THEN
    /* handle error situation */
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